This invention relates generally to the field of underground trenching and more particularly but not by way of limitation to endless cutting chains used in cutting and removing subterranean matter in forming a trench.
Underground trenching apparatus for excavating trenches are well known in the art. Trenches are excavated to lay pipe, utility and cable lines, curb preparation and other like purposes. The conventional underground trenching machines usually includes a frame, a chain, a plurality of cutting teeth and a power transmission. The frame has ground-engaging wheels and the boom is attached to and extends outwardly from the frame. The chain extends around the periphery of the boom in much the same manner as a chain that extends around the bar of a chain saw.
The plurality of cutting teeth are mounted on the chain and the transmission is mounted on the frame. The transmission is used for driving the chain around the boom such that the chain can dig a trench in the ground. Typically, the boom is movable between a raised position in which the cutting teeth do not contact the ground and a lowered position in which the cutting teeth engage the ground. In the lowered position, as the cutting teeth engage and loosen the soil, the teeth and chain drag the loosened ground material to the surface where a conveying auger moves the ground materials to the side of the trench.
Another such prior art trenching apparatus includes a cutting chain with a plurality of cutting links, with each cutting link having a planar flat surfaced plate to mount the cutting teeth. This type of a cutting chain will cause a flat bottom trench to be excavated. It is desirable to provide an improved cutting chain of the type described in the present invention that provides for excavation of a round bottom trench.
Additionally, because of the planar, flat surface of the mounting plates of each cutting link, the loose dirt, spoils or broken materials are not effectively conveyed out of the trench by the cutting chain. Therefore, it is desirable to provide an improved cutting chain of the type described in the present invention that provides a cost effective and time efficient mechanism to more effectively drag the dirt, spoils, broken materials, etc. to the surface thereby producing a much cleaner trench and improving the trenching performance of the cutting chain.
Also, it is well known in the prior art to employ one or two cutting teeth for each cutting link of the cutting chain. The cutting teeth may be arranged longitudinally on a support surface of some sort of each cutting link. The cutting teeth are then secured to the support surface generally by fasteners or other retaining means. However, the fasteners are often loosened during operation of the cutting chain thereby necessitating repeated tightening of the fasteners.
Additionally, in other prior art trenching apparatuses, the cutting teeth are detachably secured in sockets by using retainers. The retainers are inserted in the socket wall and compressed between the cutting tooth and the socket wall. However, this securing mechanism substantially restricts the number of cutting teeth that may be secured on the support surface of each cutting link due to the mass of the socket and access to the retainers. Also, the selection of lateral positions available to the cutting tooth for attachment on the support surface are limited.
Thus there exists a need in the industry to provide an improved cutting chain of the type described in the present invention that provides for more flexibility for mounting cutters on a support surface of a cutting link. These and other further advantages of the present invention will become apparent to those skilled in the art from the following detailed description and drawings.
The present invention is directed to a cutting chain comprising a plurality of cutter links with a strap link joining adjacent cutter links forming an endless chain. At least one cutter link of the cutting chain comprises a pair of side plates, a support member, at least one cutting member, and a drag plate. The support member bridges the side plates and has an arcuate support surface. At least one cutting member is attached onto the arcuate support surface of the support member. Additionally, the drag plate is attached to the support member.
In another aspect, the present invention is directed to a cutter link for a cutting chain. The cutter link comprises a pair of side plates, a support member; at least one cutting member, and a drag plate. The support member is arcuately shaped and bridges the side plates. At least one cutting member is attached onto the support member. Additionally, the drag plate is attached to the support member.
In still another aspect, the present invention is directed to a cutting chain comprising a plurality of cutter links forming an endless chain. At least one cutter link of the endless cutting chain comprises a support member, wherein the support member has a pair of side sections, a bridge section, and a plurality of cutting members. The pair of side sections is spaced apart and planar. The bridge section is interposed between the side sections and has an arcuate support surface formed in a medial portion thereof. The plurality of cutting members is supported by the arcuate support surface.
The invention is further directed to a cutter link for a cutting chain comprising a support member and a plurality of cutting members. The support member has an arcuate support surface. The plurality of cutting members is disposed in laterally offset relationship at substantially the same longitudinal position on the arcuate support surface. Additionally, the support member and the cutting members are adapted to permit substantially unrestricted selection of the lateral position of each cutting member on the arcuate support surface of the support member.
In yet another aspect, the present invention is directed to a cutting chain comprising a plurality of cutter links with a strap link joining adjacent cutter links to form an endless chain. At least one cutter link of the endless cutting chain comprises a pair of side plates, a support member, and a drag plate. The support member bridges the side plates and has an arcuate support surface. Additionally, the support member is characterized by an unobstructed arcuate interior passage that extends substantially parallel to the direction of travel of the cutting chain. The drag plate is attached to the support member.
In still another aspect, the present invention is directed to a cutting chain comprising a plurality of cutter links. A strap link joins adjacent cutter links using a pair of fastening members to form an endless chain. At least one cutter link of the endless chain comprises a pair of side plates, a support member, and a drag plate. The support member bridges the side plates. Further, the drag plate comprises an upper arcuate portion and a pair of side portions. The upper arcuate portion is attached to the support member. The pair of side portions extend downward from the upper arcuate portion. Additionally, each side portion is attached to and extends outwardly from a corresponding side plate such that each side portion forms a shield for the corresponding fastening number.